While your average student is enjoying a beer in the sun on this sultry summer evening, Xavier Köhlen is working up a sweat at boxing club De Amateur in Munstergeleen. The 23-year-old Limburger of Moluccan descent is not only a top boxer with a cabinet full of trophies, but also a second-year student of Tax Law at Maastricht University (UM) and a fourth-year student of Sport and Physical Education at the Eindhoven University of Applied Sciences.

Could you describe your research?
The central question is: which measures encourage people to work for longer and which do not? The restriction of pension rights in the public sector in 2006 in an attempt to encourage working longer shows a negative effect on work motivation. People who only just missed out on a "broader" retirement turn out to be often more depressed than those who just keep this right.

Could you describe your research?
I am involved in the European and National Constitutional Law (EUNACON) project. This is a four-year EU financed project, led by professor Monica Claes and comprised of three other colleagues in the law faculty. We examine fundamental constitutional principles in ten Member States and in the EU.

Could you describe your research?
I study the effectivity of Dutch policy in the area of school dropouts. In 2000, the European Council decided to halve the number of pupils without a starting qualification by 2010, which has really drawn attention to the issue. As a result, the EU member states have developed various programmes to reduce high school dropouts. Including the Netherlands – the number of dropouts here dropped from 15.4% in 2000 to 10.1% in 2010.

Could you describe your research?
I’ve just received a Veni grant to study the link between arteriosclerosis and overweight. We know that overweight people have a greater chance of developing cardiovascular diseases. And it’s agreed that this is at least partly caused by chronic inflammation in the fatty tissue of overweight people. But what’s actually happening at the cell level is not yet clear.

Could you describe your research?
I study different types of aggression. What triggers it, what happens at that particular moment in an individual’s body and mind, how to measure aggression in a lab situation, those sorts of questions. Broadly speaking, there are two types of aggression: impulsive and planned.

Could you describe your research?
I am interested in why states voluntarily delegate tasks in the area of international security to organisations such as the EU, NATO and the United Nations. Traditionally, sovereignty is held in high regard. Your present ally can become your enemy tomorrow, so to speak. Even so, thousands of civil servants work for these kinds of organisations. What exactly do they contribute? Under what conditions do member states delegate these kinds of tasks? And why does NATO have such a heavily manned headquarters with fifteen thousand staff while the UN, which deploys as many troops, does not?

Could you describe your research?
I study the extent to which people are able to assess their own learning. This skill is known as metacognition. Generally speaking, students – particularly the poorest performing students – tend to greatly overestimate their performance when asked how they think they scored on a test. Overestimation leads to less learning, and thus to worse performance.